I just went through this exercise. We're not running storm-control on any unicast traffic. If you need to do this to make sure a certain user doesn't hog an uplink to the core, I guess there's a point in that, but I'd rather apply big enough uplinks to the core, rather than throttle their bandwidth.
If you search the NetPro forums, you'll see some posts I did earlier today on exactly this topic. For broadcast and multicast thresholds, we've sort of settled on 20% for gigabit host ports and 30% for trunk/uplink gigabit ports. But that's because after some testing, we decided that to be appropriate for our network.
Cisco's TAC recommended to make a baseline of your network, so that you know what "normal" broadcast/multicast/unicast traffic levels are, and then put your storm-control values in from there.
